Oracle profiler without 3rd party software - oracle

Question

I am trying to make something like T-SQL profiler with queries without any 3rd party software.
So first of all I have code for take currently executed queries:
select x.sid
,sql_text
from v$sqlarea sqlarea
,v$session x
where x.sql_hash_value = sqlarea.hash_value
and x.sql_address = sqlarea.address
and x.username = 'USERNAME';
Now I find two challenges:
When I put this code in while loop I am getting error:
DECLARE
x NUMBER := 0;
BEGIN
LOOP
select x.sid
,sql_text
from v$sqlarea sqlarea
,v$session x
where x.sql_hash_value = sqlarea.hash_value
and x.sql_address = sqlarea.address
and x.username = 'MAGICAPP';
EXIT WHEN x > 1;
END LOOP;
END;
Error report - ORA-06550: line 5, column 10: PLS-00428: an INTO clause
is expected in this SELECT statement
06550. 00000 - "line %s, column %s:\n%s"
*Cause: Usually a PL/SQL compilation error.
*Action:
Second challenge might be:
Even if this code above works it would keep refreshing old data with new data by SELECT statement. Would it be possible to append new data to old data with SELECT statement if new data is not found in old data?
How this should work?
Once executed this script should keep running while user not cancel it and than print all queries which it found.

Answer 1

For the error specifically you need an INTO to SELECT the values INTO variables, something like:
DECLARE
x NUMBER := 0;
txt VARCHAR2(4000);
BEGIN
LOOP
select x.sid,sql_text
INTO x, txt
from v$sqlarea sqlarea
,v$session x
where x.sql_hash_value = sqlarea.hash_value
and x.sql_address = sqlarea.address
and x.username = 'MAGICAPP';
EXIT WHEN x > 1;
END LOOP;
END;